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Azobenzene

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https://www.readbyqxmd.com/read/28543683/photo-responsive-soft-ionic-crystals-ion-pairing-assemblies-of-azobenzene-carboxylates
#1
Ryohei Yamakado, Mitsuo Hara, Shusaku Nagano, Takahiro Seki, Hiromitsu Maeda
This report delineates the design and synthesis of negatively charged azobenzene derivatives that form photo-responsive ion-pairing assemblies. The azobenzene carboxylates possessing aliphatic chains were prepared as photo-responsive anions that promote the formation of ion-pairing dimension-controlled assemblies, including mesophases, when used in conjunction with a tetrabutylammonium (TBA) cation. The photo-responsive properties of the ion pairs and the precursory carboxylic acids in the bulk state were examined by POM and XRD, demonstrating that liquid crystal (LC)-liquid and crystal-liquid phase transitions occurred depending on the number and lengths of the aliphatic chains of each assembly...
May 23, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28534912/prediction-on-the-light-assisted-exfoliation-of-multilayered-arsenene-by-the-photo-isomerization-of-azobenzene
#2
Jun Zhao, Chunyan Liu, Wanlin Guo, Jing Ma
The exfoliation of gray arsenic into single- or few-layered arsenene is a challenge of utmost importance. We propose here that the conformational change in the photo-isomerization of azobenzene-based photochromes might be used to promote the exfoliation of multilayered arsenene. Our density functional theory calculations show that the trans-to-cis conformational change can lead to an increase of the adjacent interlayer distance of arsenene from 6.59 Å to 11.07 Å. Starting from the transition state, the azobenzene molecule can be isomerized into the more stable trans form based on further ab initio molecular dynamics simulations...
May 23, 2017: Nanoscale
https://www.readbyqxmd.com/read/28524194/chiral-supramolecular-organization-from-a-sheet-like-achiral-gel-a-study-of-chiral-photoinduction
#3
Jorge Royes, Víctor Polo, Santiago Uriel, Luis Oriol, Milagros Piñol, Rosa M Tejedor
Chiral photoinduction in a photoresponsive gel based on an achiral 2D architecture with high geometric anisotropy and low roughness has been investigated. Circularly polarized light (CPL) was used as a chiral source and an azobenzene chromophore was employed as a chiral trigger. The chiral photoinduction was studied by evaluating the preferential excitation of enantiomeric conformers of the azobenzene units. Crystallographic data and density functional theory (DFT) calculations show how chirality is transferred to the achiral azomaterials as a result of the combination of chiral photochemistry and supramolecular interactions...
May 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28517106/tunable-supramolecular-assembly-and-photoswitchable-conversion-of-cyclodextrin-diphenylalanine-based-1d-and-2d-nanostructures
#4
He-Lue Sun, Yong Chen, Xu Han, Yu Liu
A photocontrolled, interconvertible supramolecular 2D-nanosheet/1D-nanotube system was constructed through the supramolecular assembly of adamantanyl-modified diphenylalanine with azobenzene-bridged bis(β-cyclodextrin). The nanosheet exhibited a greater fluorescence enhancement effect than the nanotube. Significantly, these nanosheets and nanotubes could interconvert via the photocontrolled trans/cis isomerization of azobenzene linkers in bis(β-cyclodextrin), and this photo-switchable one-dimensional/two-dimensional morphological interconversion was reversible and recyclable...
May 18, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28510314/a-photoswitchable-dualsteric-ligand-controlling-receptor-efficacy
#5
Luca Agnetta, Michael Kauk, Maria Consuelo Alonso Canizal, Regina Messerer, Ulrike Holzgrabe, Carsten Hoffmann, Michael Decker
The investigation of the mode and time course of the activation of G-protein-coupled receptors (GPCRs), in particular muscarinic acetylcholine (mACh or M) receptors, is still in its infancy despite the tremendous therapeutic relevance of M receptors and GPCRs in general. We herein made use of a dualsteric ligand that can concomitantly interact with the orthosteric, that is, the neurotransmitter, binding site and an allosteric one. We synthetically incorporated a photoswitchable (photochromic) azobenzene moiety...
May 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28509394/room-temperature-oligomeric-discotic-nematic-liquid-crystals-over-a-wide-temperature-range-structure-property-relationships
#6
Santanu Kumar Pal, Monika Gupta, Santosh Prasad Gupta, Subhransu Sekhar Mohapatra, Surajit Dhara
Design and synthesis of three room-temperature discotic nematic (ND) liquid crystals (LCs) is presented consisting of an azobenzene core attached to which are four pentaalkynylbenzene (PA) units via flexible alkyl spacers. The presence of short azo linking group provides more disorder in the system, thereby reducing the packing efficiency among the PA units and resulting into the formation of a room-temperature ND phase over a wide temperature range. Dielectric constant and birefringence studies were performed to gain further insights into the physical properties of the mesophase...
May 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28508454/light-mediated-reversible-modulation-of-ros-level-in-living-cells-by-using-an-activity-controllable-nanozyme
#7
Faming Wang, Enguo Ju, Yijia Guan, Jinsong Ren, Xiaogang Qu
Nanozymes have shown great potential in bioapplications owing to their low cost, high stability, multiple activity, and biocompatibility. However, most of the known nanozymes are always at turn-on state, hindering their further applications. Herein, a simple and versatile method for constructing activity-controllable nanozymes is presented. To the best of our knowledge, this is the first report to utilize the light-driven isomerization of azobenzene (Azo) and host-guest interaction to reversibly photoregulating the activity of nanozyme...
May 16, 2017: Small
https://www.readbyqxmd.com/read/28503686/mesoporous-nanocarriers-with-a-stimulus-responsive-cyclodextrin-gatekeeper-for-targeting-tumor-hypoxia
#8
Jeonghun Lee, Eun-Taex Oh, Haerry Yoon, Chan Woo Kim, Yeji Han, Jaehun Song, Hyunil Jang, Heon Joo Park, Chulhee Kim
Tissue hypoxia developed in most malignant tumors makes a significant difference to normal tissues in the reduction potential and the activity of various bioreductive enzymes. Given the superior enzymatic activity of NAD(P)H:quinone oxidoreductase 1 (NQO1, a cytosolic reductase up-regulated in many human cancers) in hypoxia relative to that in normoxia, NQO1 has great potential for targeting hypoxic tumor cells. In the present report, the core concept of hypoxic NQO1-responsive mesoporous silica nanoparticles (MSNs) is based on the reasoning that the superior enzymatic activity of NQO1 within hypoxic cancer cells can be utilized as a key stimulus for the selective cleavage of an azobenzene stalk triggering the on-off gatekeeping for controlled release of guest drugs...
May 25, 2017: Nanoscale
https://www.readbyqxmd.com/read/28488694/light-induced-unfolding-and-refolding-of-supramolecular-polymer-nanofibres
#9
Bimalendu Adhikari, Yuki Yamada, Mitsuaki Yamauchi, Kengo Wakita, Xu Lin, Keisuke Aratsu, Tomonori Ohba, Takashi Karatsu, Martin J Hollamby, Nobutaka Shimizu, Hideaki Takagi, Rie Haruki, Shin-Ichi Adachi, Shiki Yagai
Unlike classical covalent polymers, one-dimensionally (1D) elongated supramolecular polymers (SPs) can be encoded with high degrees of internal order by the cooperative aggregation of molecular subunits, which endows these SPs with extraordinary properties and functions. However, this internal order has not yet been exploited to generate and dynamically control well-defined higher-order (secondary) conformations of the SP backbone, which may induce functionality that is comparable to protein folding/unfolding...
May 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28482565/photoresponsive-hollow-molecularly-imprinted-polymer-for-trace-triamterene-in-biological-samples
#10
Cheng-Bin Gong, Yu-Bo Wei, Lan-Tao Liu, An-Xun Zheng, Yue-Hong Yang, Cheuk-Fai Chow, Qian Tang
This paper reports a photoresponsive hollow molecularly imprinted polymer for the determination of trace triamterene in biological sample. The photoresponsive hollow molecularly imprinted polymer was prepared on sacrificial silica microspheres via surface imprinting technique through atom transfer radical polymerization using a novel water-soluble azobenzene derivative, 4-[(4-methacryloyloxy)phenylazo]-3,5-dimethyl benzenesulfonic acid, as the functional monomer, and the sacrificial silica core was subsequently removed using HF etching method with 1...
July 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28475310/novel-light-responsive-biocompatible-hydrogels-produced-by-initiated-chemical-vapor-deposition
#11
Katrin Unger, Paul Salzmann, Cecilia Masciullo, Marco Cecchini, Georg Koller, Anna Maria Coclite
A novel multiresponsive hydrogel has been synthesized by initiated chemical vapor deposition (iCVD). Hydrogels are known for their dynamic swelling response to aqueous environments. A chemical functionalization of the hydrogel surface was performed to add other stimuli-responsive functionalities and obtain a smart material that responds to two stimuli: light irradiation and exposure to aqueous environment. Modifying the hydrogel surface with solution-based methods is often problematic because of the damages caused by the permeation of solvents in the hydrogel...
May 12, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28467094/porphyrin-azobenzene-bodipy-triads-syntheses-structures-and-photophysical-properties
#12
Bangshao Yin, Taeyeon Kim, Mingbo Zhou, Weiming Huang, Dongho Kim, Jianxin Song
Cyclic and acyclic azobenzene bridged porphyrin-dipyrrin derivatives were successfully prepared via Suzuki-Miyaura coupling reaction of α,α'-diborylated dipyrromethane with bromoazophenyl porphyrin or reaction of borylated porphyrin with dibromoazophenyl dipyrrin, and the corresponding porphyrin-Bodipy derivatives were obtained by subsequent boron complexation. The cyclic porphyrin-dipyrrin compound 3Ni was confirmed by X-ray diffraction. The low fluorescence quantum yields of azobenzene bridged porphyrin-Bodipy can be ascribed to the presence of the intramolecular charge transfer state...
May 3, 2017: Organic Letters
https://www.readbyqxmd.com/read/28463372/silver-and-palladium-alloy-nanoparticle-catalysts-reductive-coupling-of-nitrobenzene-through-light-irradiation
#13
Sunari Peiris, Sarina Sarina, Chenhui Han, Qi Xiao, Huai-Yong Zhu
Silver-palladium (Ag-Pd) alloy nanoparticles strongly absorb visible light and exhibit significantly higher photocatalytic activity compared to both pure palladium (Pd) and silver (Ag) nanoparticles. Photocatalysts of Ag-Pd alloy nanoparticles on ZrO2 and Al2O3 supports are developed to catalyze the nitroaromatic coupling to the corresponding azo compounds under visible light irradiation. Ag-Pd alloy NP/ZrO2 exhibited the highest photocatalytic activity for nitrobenzene coupling to azobenzene (yield of ∼80% in 3 hours)...
May 2, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28463008/polymeric-nanocarriers-based-on-cyclodextrins-for-drug-delivery-host-guest-interaction-as-stimuli-responsive-linker
#14
Liao Peng, Senyang Liu, Anchao Feng, Jinying Yuan
Stimuli responsive polymers have been extensively studied as nanocarriers for drug delivery systems (DDSs), especially those based on supramolecular interactions. Cyclodextrin (CD) is one kind of widely applied host molecules and the host-guest interactions between CD and different counterparts can respond to different stimuli, thus can be applied as responsive linkers for polymeric DDSs. In this review, the polymeric nanocarriers based on the host-guest interactions between cyclodextrin and ferrocene, azobenzene and benzimidazole as DDSs are summarized, with redox, light and pH sensitivity respectively...
May 2, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28456201/light-responsive-expansion-contraction-of-spherical-nanoparticle-grafted-with-azopolymers
#15
Jie Fu, Xinghua Zhang, Bing Miao, Dadong Yan
Due to the very importance for both fundamental research and technological applications, smart materials with stimuli-responsive properties have been studied intensively. Theoretical investigation contributes to this endeavor through constructing and analyzing a model system which captures main features of the corresponding complex material, wherefrom useful insight can be provided to the trial-and-error experiments. We here report a theoretical study on the smart spherical nanoparticle grafted with light-responsive azobenzene-containing polymers...
April 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28451180/photochromic-torsional-switch-pts-a-light-driven-actuator-for-the-dynamic-tuning-of-%C3%AF-conjugation-extension
#16
Jan Maciejewski, Adam Sobczuk, Alexis Claveau, Adrien Nicolai, Riccardo Petraglia, Luca Cervini, Emilie Baudat, Pascal Miéville, Daniele Fazzi, Clemence Corminboeuf, Giuseppe Sforazzini
Here we present a molecular architecture that can reversibly change the geometric conformation of its π-system backbone via irradiation with two different wavelengths. The proposed 'molecular actuator' consists of a photoswitchable azobenzene orthogonally connected to a π-conjugated bithiophene by both direct and aliphatic linker-assisted bonding. Upon exposure to 350 nm light, the trans azobenzene moiety isomerizes to its cis form, causing the bithiophene to assume a semiplanar anti conformation (extended π-conjugation)...
January 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28425541/photoisomerisation-and-light-induced-morphological-switching-of-a-polyoxometalate-azobenzene-hybrid
#17
Grzegorz Markiewicz, Dawid Pakulski, Agostino Galanti, Violetta Patroniak, Artur Ciesielski, Artur R Stefankiewicz, Paolo Samorì
The functionalization of a spherical Keplerate-type polyoxometalate {Mo72V30} with a cationic azobenzene surfactant has been achieved through ionic self-assembly. The photoisomerisation reaction of this complex, which emerges in a light-triggered aggregation-disaggregation process, has been followed by (1)H NMR spectroscopy, dynamic light scattering, absorption spectroscopy and scanning electron microscopy analyses.
April 20, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28421212/cp-co-iii-catalyzed-ortho-amidation-of-azobenzenes-with-dioxazolones
#18
Gongutri Borah, Preetismita Borah, Pitambar Patel
Cp*Co(iii)-catalyzed C-H amidation of azobenzene with dioxazolones has been developed. The amidation reaction does not require external oxidants and gives carbon dioxide as the only by-product. Both symmetrical and unsymmetrical azobenzenes were found to undergo amidation smoothly with broad functional group tolerance.
May 10, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28416130/ph-dependant-fluorescence-switching-of-an-i-motif-structure-incorporating-an-isomeric-azobenzene-pyrene-fluorophore
#19
Han Na Joo, Thuy Van Thi Nguyen, Hyeon Kyeong Chae, Young Jun Seo
In this study, we synthesized an Azo-py phosphoramidite, featuring azobenzene and pyrene units, as a novel fluorescent and isomeric (trans- and cis-azobenzene units) material, which we incorporated in an i-motif DNA sequence. We then monitored the structural dynamics and changes in fluorescence as the modified DNA sequences transformed from single strands at pH 7 to i-motif quadruplex structures at pH 3. After incorporating Azo-py into the 4A loop position of an i-motif sequence, dramatic changes in fluorescence occurred as the DNA structures changed from single-strands to i-motif quadruplex structures...
April 6, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28414225/reversible-gas-solid-ammonia-n-h-bond-activation-mediated-by-an-organopalladium-complex
#20
Marina Juribašić Kulcsár, Ivan Halasz, Ana Budimir, Krunoslav Užarević, Stipe Lukin, Andrea Monas, Franziska Emmerling, Janez Plavec, Manda Ćurić
N-H bond activation of gaseous ammonia is achieved at room temperature in a reversible solvent-free reaction using a solid dicyclopalladated azobenzene complex. Monitoring of the gas-solid reaction in real-time by in situ solid-state Raman spectroscopy enabled a detailed insight into the stepwise activation pathway proceeding to the final amido complex via a stable diammine intermediate. Gas-solid synthesis allowed for isolation and subsequent structural characterization of the intermediate and the final amido product, which presents the first dipalladated complex with the Pd(II)-(μ-NH2)-Pd(II) bridge...
April 17, 2017: Inorganic Chemistry
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